| 摘要: |
| 海岸线是海陆分界线，定义为多年平均大潮高潮位的痕迹线，兼具海洋与陆地的空间资源管理界限功能。海岸线具有重要的生态功能和资源价值，其功能和价值源于所依附的海岸带。随着海岸带地区的经济与社会快速发展，海岸带资源的保护与开发的矛盾日益凸显。在此背景下，中国构建了以自然岸线保有率为核心的海岸线管理办法。2018年实施的浙江省地方标准《海岸线调查统计技术规范（DB33/T 2106-2018）》提出了海岸线的三级分类体系，包括自然岸线、人工岸线和河口岸线3个一级类。该《规范》综合反映了海岸线的科学定义和国家需求。首先，该《规范》给出海岸线定义是"平均大潮高潮时水陆分界的痕迹线"，突出了"大潮高潮位"和"痕迹线"对海岸线界定工作的指示意义。其次，该《规范》将自然岸线定义为"由海陆相互作用形成的海岸线"，由此推论，人工岸线的地貌动力学功能是隔断了原有的海陆相互作用。第三，该《规范》提出了"原生自然岸线"、"自然恢复的岸线"和"整治修复的岸线"等概念，将曾经受过人类活动影响但恢复了（或拥有了）某种自然海岸形态特征和生态功能的岸线纳入自然岸线的统计口径。由于河口岸线是没有"水陆分界痕迹"可循的特殊类型，现有的海岸线定义未能体现河口岸线的内涵，因此我们建议将海岸线的定义扩展为"平均大潮高潮位的海陆分界痕迹线，以及河流入海口附近按一定规则人为划分的海域与陆域水体的分界线"。从海岸带地貌动力学的角度来看，海岸线的类型和变化主要受地质基底、海平面位置、沉积物供应条件和海岸动力环境等因素影响。因此，海岸线的定义和分类应该综合考虑这四个因素，而人类活动主要从海岸动力作用环境和沉积物供应条件两方面影响海岸带系统状态。 |
| 关键词: 海岸线|海岸带|地貌形态|生态功能|人类活动 |
| DOI：10.11759/hykx20190113001 |
| 分类号:P748 |
| 基金项目:国家自然科学基金面上项目（41876092） |
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| A classification of coastline considering the impacts of human activities: remarks on latest practices on coastline survey in Zhejiang Province |
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JIA Jian-jun1, CAI Ting-lu2, LIU Yi-fei2, CHEN Yi-ning2, WANG Xin-kai2, MEI Ya-ping1, SHI Lian-qiang2, XIA Xiao-ming2
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1.State Key Laboratory for Estuarine and Coastal Research, East China Normal University, Shanghai 200241, China;2.State Centre for Island Exploitation and Management, Second Institute of Oceanography of Ministry of Natural Resources, Hangzhou 310012, China
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| Abstract: |
| A coastline is the boundary separating two parts of the Earth's surface:land and ocean. It is also the administrative boundaries between land and maine space resources. Coastlines are significant in terms of ecological functions and spatial resources, which are derived from the coastal zone to which they are attached. With the rapid development of the economy and society in coastal areas, the contradiction between protection and utilization of coastal resources has increased significantly. Against this background, the China central government has established a coastline control regulation; herein, the percentage of natural coastline is the key issue to evaluate whether this regulation will meet with success. Correspondingly, Zhejiang Province issued a provincial standard stipulating terms and definations, procedures and statistical methods for coastline survey, in which a three-level classification system for coastlines was proposed. Natural, artificial, and estuarine coastlines are identified as the first-level categories of coastline. This provincial standard reflects the scientific definition of coastlines and administrative needs on maintaining the percentage of natural coastline. First, the standard defines a coastline as "the trace line of the mean high water level of spring tides marking the boundary between land and ocean, " which highlights the significance of "the high water of spring tides" and "the trace line" in the recognition of coastlines. Second, the standard defines natural shorelines as "coastlines formed via the interaction of the land and sea." Thus, it can be inferred that the morphodynamic function of artificial shorelines is to break the interaction between sea and land. Third, the standard proposes three subordinary categories of natural coastline, i.e., "original natural shorelines", "restored natural shorelines" and "rehabilitated and regulated shorelines". In this way, those specific coastlines that were once affected by human activities but have restored certain natural morphological features and ecological functions can be classified as natural coastlines. In order to include the connotation of estuarine coastline in the definition of coastline, an extended one was proposed in this paper that a coastline is "the trace line of the mean high water level of spring tides marking the boundary between land and ocean and the artificial delimited boundary between seawater and river water within an estuary." From the perspective of a coastal morphodynamic system, the factors affecting coastlines are geological background, sea level, coastal dynamics, and sediment supply. In the timescale of routine coastline surveys, the influences of human activities on coastal systems are mainly demonstrated with changes of two aspects:coastal dynamics and sediment supply. Therefore, we should take these factors into consideration while giving a definition and classification on coastline. |
| Key words: coastline coastal zone geomorphology ecological function human activities |
